Bearing



Patented Sept. 13, 1927.

UNITED STATES garsu'r om n HARRY H. WILLIAMS AND ALFRED L. BOEGEHOLD, OI DAYTON, OHIO, ASBIGNOEB TO GENERAL MOTORS RESEARCH CORPORATION, OF DAYTON, OHIO, A OOBPOMTIQI OI DELAWABE.

Bennie.

Jlo Drawing.

The objects of the invention include a bushing or bearing or the like capable of containin within itself a large reserve supply of In ricant which lubricant is applied uniformly to the sliding surfaces.

Another object is a bushing or like member of this character that will permit replenishing this reserve from external sources.

Still another object is a bushing or member of this character made of a material that will withstand high bearing pressures, having machinability, a low coeflicient of friction, toughness and ductility.

A further object is an eflicient and economical process of producing such materials and the formation therefrom of such bushings or like members. 1

In the preferred form of embodiment of the invention the material is a coherent-body of highly porous metallic alloy structure, having a low coeflicient of friction and a high crushing strength combined with the properties of toughness, ductility and machinability.

The porosity is due to the existence of a large number of minute voids in the metal structure. In other words, the material is a minutely cellular coherent structure whose cells are microscopic in size and are intercommunicating and whose walls are of bearin metal, for example, bronze.

e high crushing strength and other (Satisfactory Application filed August 17, 1922. Serial Io. 582,550.

properties mentioned are functions of the alloy formed and will vary therewith and :v1th modifications in the process of producion.

Anexample of the crushin stre h that has been found is about 7 5,005 lbs. sq. in.

Sucha material as has just been mentloned admits of great possibilities from the standpomt of lubrication. It readily takes up large quantities of oil which it gives u to the. bearin surface only as neede I ushin s having an oil absorptlon up to 17% ave been made.) It may be impregnated with any lubricant su1table for the specific requirements of the service in which the bushing or hearing is to be used. For example, for this pur se may be used any liquid lubricant or lu ricant which 1s solid at normal atmospheric temperatures but which melts at shghtly elevated temperatures, such as stearic acid, petroleum elly, soaps, etc.; ,or a material such as that marketed under the trade name of Oildag which will supply to the hearng surface both oil and lubricating graphite 1n suspension. (Oildag is broadly a suspension of graphite in oil.)

Impregnation with Aquadag followed by a drylng operation also gives good results. Aquadag is broadly a suspension of grap ite in water.)

Materials such as above described and wh ch form part of the, invention herein clalmed may be produced in the following manner.

Metals in a fine state of subdivision are first mixed together and with a small 'ro port on of a material which will volati ize, sublime, or otherwise separate from the metalllc mass in a subsequent heating and which will have no deleterious effect on the other constituents or on the product. This mixture is then compressed in suitable dies to form a coherent mass of the desired shape and the formed articles subjected to heating under suitable conditions to cause the metals to diffuse or alloy together and the volatile material to be drlven out. The

Iproportions used for a bearing bushing is as ollows Parts.

Salicylic acid 6 It has been found that good results are obtained if these materials in a state of division fine enou h to pass a 200 mesh screen, are intimatedy mixed in any suitable fashion and compressed in a die of the desired form under very high pressure, for example 80,000 lbs. (per sq. in. The formed article is then heate in a non-oxidizing atmosphere for a suflicient period to cause the desired alloying. When heating at say 675 0., which has been found a satisfactory temerature, a period of about 3 hours has prouced a satisfactor product although longer heating is not ob ectionable. The time of heating at this tem erature will usually be from 3 to 6 hours a though even longer perriods are not detrimental. If, however, the temperature is increased, the time may be materially shortened.

The bushing is then allowed to cool, and may be machined to size by reaming or other convenient method and impregnated with lubricant and is then ready for installation.

The method to be used for impregnating the bushin may be any of the ordinary methods 0 impregnating porous materials. Good results have been obtained by heating the bushings in oil and allowing them to cool therein and also by well known vacuum and pressure methods.

The process is quite well adapted for the production of bearings of many difi'erent compositions by varying the several factors of composition, briquetting pressure, temprature and time.

Graphite may also be used and a typlcal mixture containing this material is:

00 r. Tti

Parts. Copper 90 Tin 10 Graphite 6 Salicylic acid 2t04 For a softer bearing material, the composition may contain lead. Bearings have been produced having up to thirty-two to thirtythree percent (32-33%) of lead. For example:

In order to control the de ee of porosity of the body produced accor ing to this invention, volatile or anic substances such as benzoic acid or nap thalene may be substituted for salicylic acid. The volatile organic substances of this character do not react with the metallic particles of the body under heat treatment, and therefore do not oxidize or corrode the particles.

By carrying out the above rocesses, there is produced a material whic consists of a minutely cellular structure of an allo which has high compressive strength, ducti ity, p0- rosity and machinability, and one which is easily and cconomicall produced.

\Vhile the above escription shows the preferred form of embodiment of the invention it should be understood that variations may be made therein without departing from the scope of the claims which.follow.

What we claim is as follows:

1. The process which comprises intimately mixing finely divided copper, tin, and salicylic acid; compressing the mixture into the desired form under a ressure of about 80,000 lbs. per sq. in., an heating the re sultant formed article to about 675 C. in a non-oxidizing atmosphere.

2. The process of making bearings which comprises intimately mixing finely divided bearing metal constituents with salicylic acid; compressing into the desired form; and heating to drive out the acid and facilitate alloying of the said constituents.

3. The process of producing a porous body which comprises, compressing a mass of finely divided, metallic, alloyable ingredients mingled with a finely divided, completely volatile organic substance, then heat treating the mass sufliciently to cause the metallic ingredients to alloy with each other and also to effect removal of said organic volatile substance.

In testimony whereof we hereto afiix our signatures.

HARRY M. WILLIAMS. ALFRED L. BOEGEHOLD. 

